步骤
cd /etc/yum.repos.d/ mv CentOS-Base.repo CentOS-Base.repo.bak curl -o CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo yum clean all yum makecache
centos 7修改yum源
原文：https://www.cnblogs.com/zh-dream/p/14856101.html
